# Photo Tone Curves & Profile Processor

> Apply levels, RGB curves and white balance, or reuse a Lumina photo profile. Develop a photo with black and white points, gamma, five-point master and RGB curves, and linear-light white-balance gains. Download a transparent PNG and reusable settings profile, or paste a profile saved from Lumina.

Part of usefulweb.site (https://usefulweb.site/). Results are deterministic calculations from the inputs and the listed assumptions; the API returns exactly what the web page shows.

## Use it
- Human interface: https://luminatoneprocessor.usefulweb.site/ (interactive tool at https://luminatoneprocessor.usefulweb.site/tool)
- JSON API: POST https://luminatoneprocessor.usefulweb.site/api/v1/calculate with a JSON object of inputs (schema: https://luminatoneprocessor.usefulweb.site/api/v1/tool)
- OpenAPI: https://luminatoneprocessor.usefulweb.site/openapi.json
- MCP (Streamable HTTP): https://luminatoneprocessor.usefulweb.site/mcp - tool `lumina_tone_processor`

## Inputs
- image (file, required): Image (PNG, JPEG or WebP; up to 8 MB and 16 MP)
- profile (textarea): Lumina profile JSON (optional; overrides all manual fields)
- black (number): Input black
- white (number): Input white
- gamma (number): Midtone gamma
- exposure (number): Exposure (EV)
- contrast (number): Contrast
- saturation (number): Saturation
- redGain (number): Red linear-light gain
- greenGain (number): Green linear-light gain
- blueGain (number): Blue linear-light gain
- master (text): Master curve outputs at 0,64,128,192,255
- red (text): Red curve outputs at 0,64,128,192,255
- green (text): Green curve outputs at 0,64,128,192,255
- blue (text): Blue curve outputs at 0,64,128,192,255

## Method
- Auto-oriented, display-referred 8-bit sRGB analysis. Fully transparent pixels are excluded; other pixels count equally.
- Luma is rounded 0.2126 R + 0.7152 G + 0.0722 B. Clipping counts any channel at or below 2, or at or above 253. This does not measure sensor exposure or recover clipped RAW data.
- A supplied Lumina profile overrides all manual fields. Otherwise apply linear-light RGB gains, existing Develop exposure/contrast/saturation, encoded-sRGB levels and gamma, master curve, then channel curves. Five fixed inputs are interpolated with straight segments; outputs may be non-monotonic.
- Gamma uses normalizedInput^(1/gamma). PNG retains the source alpha and omits source metadata. Profiles contain only adjustments and tone settings; camera PP3, RAW and ICC profiles are not supported.